The present technology relates to a battery, a battery pack, an electronic device, an electric vehicle, an electricity storage device, and a power system in which electrodes to which electrode composite materials are applied are wound and accommodated in a laminate exterior member.
The energy density of a battery can be improved by decreasing the proportion of members that are not involved in charging and discharging inside a battery pack. If, however, the thickness of foil or a separator is reduced, the safety against nail penetration is lowered. Thus, in order to obtain a battery where the safety is secured, the thicknesses of such members need to be maintained at certain thickness or larger.
A structure in which a positive electrode current collector and a negative electrode current collector on which no active material containing coating film is formed are arranged with a separator therebetween on an outermost periphery of a battery having a wound structure (hereinafter referred to as a “wound foil structure”) has been proposed (refer to Patent Document 1, for example).